Search

Purpose: Clear cell sarcoma (CCS) of tendons and aponeuroses and CCS-like malignant gastrointestinal neuroectodermal tumor/sarcoma (GINET) are characterized by frequent local and distant relapses, alongside with low efficacy of all systemic treatments. We aimed to collect a comprehensive dataset to identify prognostic factors and treatment outcomes., Methods: We performed a retrospective single center analysis for diagnosed CCS and GINET on demographic, tumor, treatment and survival data., Results: We identified 43 patients (w:25, m:18) with a median follow-up of 35mo and a 5y-OS-rate of 42%. At diagnosis the median age was 42yrs. Median tumor size was 3.6 cm (0.3-11.1 cm), and 24/26 (94%) tissues analyzed at our institute were EWSR1::ATF1-translocation-positive. Distant extremities (incl. knee or elbow) were affected in 72.5%. Of note, 79.5% received an excisional biopsy (benign histology suspected in 30.2%) leading to frequent incomplete resection. Final R0 status correlated significantly (p = 0.017) with longer survival rates compared to R + status in localized CCS (N0M0, 5-yr OS 0% vs 64%). Radiation and systemic treatment had limited antitumor effects while isolated limb perfusion was active in some patients. 18.6% of patients showed lymphatic spread and 20.9% distant metastases. Presence of initial M + was associated with a dismal survival of 1.4 years (M +) vs 7.1 years (M0; p < .001)., Conclusion: We here present one of the largest clinical cohorts of patients with CCS/GINET. Our data underscores the exceptional risk of metastatic disease even in small tumors. As systemic treatment and radiation showed limited efficacy, complete resection was the most important treatment option., Competing Interests: Declarations Conflict of interest No other potential conflicts of interest were reported. The authors declare no competing interests., (© 2024. The Author(s).)

Background: Reverse shoulder arthroplasty is an established procedure for patients with rotator cuff tear arthropathy. However, the repair of the subscapularis tendon remains a controversial and frequently discussed topic. This prospective randomized study was conducted to evaluate the clinical benefit of the subscapularis repair after reverse shoulder arthroplasty., Methods: Fifty patients (36 female and 14 male) were randomized and assigned to either the "repaired" (rep) or the "not repaired" (nrep) cohort. Intraoperatively, the subscapularis tendon was reattached in the rep cohort with 4 tendon-to-tendon sutures, whereas no repair was performed in the nrep cohort. The Constant-Murley Score (CS) and the range of motion were evaluated preoperatively as well as 12 and 36 months postoperatively. The Subjective Shoulder Value and the Lift-off test were performed 36 months postoperatively. The postoperative subscapularis integrity was assessed sonographically., Results: Twelve months postoperatively the rep cohort presented better results in the CS (rep: 71 vs. nrep: 66, P = .037). The normalized CS was 80% in the rep cohort and 75% in the nrep cohort (P = .114). At our last follow-up after 36 months, we did not find significant differences between the rep cohort and the nrep cohort in the CS (rep: 76 vs. nrep: 75, P = .285) and normalized CS (rep: 91% vs. nrep: 91%, P = .388). Concerning internal rotation (in points), the rep cohort achieved better results than the nrep cohort (rep: 7.3 vs. nrep: 6.6, P = .040). Flexion (rep: 145° vs. nrep: 151°, P = .826), abduction (rep: 135° vs. nrep: 137°, P = .816), external rotation (rep: 34° vs. nrep: 37°, P = .817), and the Subjective Shoulder Value (rep: 81% vs. nrep: 77%, P = .398) presented no significant differences between the cohorts. The ultrasound examination after 36 months displayed an intact tendon in 70%., Conclusions: Although the subscapularis repair affects the postoperative internal rotation positively, there were no differences in midterm follow-up concerning the overall results after reverse total shoulder arthroplasty. Further, the external rotation is not affected by the repair of the subscapularis tendon., (Copyright © 2024 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

This study aimed to retrospectively analyze the follow-up results of cases in which the adjacent joint was preserved using a custom-made uncemented short-stem design (hollow stem) with optional external flanches in tumor endoprosthetic replacement due to bone sarcomas in 13 patients (with an average age of 9.6 years) between 2017 and 2023. Reconstructions were proximal femur ( n = 6), intercalary femur ( n = 4), intercalary tibia ( n = 2), and proximal humerus ( n = 1) tumor prostheses. The hollow body was used distally in 10 of the megaprotheses, proximally in 1, and both proximally and distally in 2 of them. The average distance from the joints was 6 cm in stems with flanches and 11.8 cm in stems without flanches. No aseptic loosening or deep infection was observed during an average follow-up of 34 months. Except for one case with a tibial intercalary prosthesis that needed a revision, all cases were well osteointegrated and all lower extremity cases could bear full weight without pain. In cases where the remaining bone stock after bone resection is insufficient for a standard stem implantation, reconstruction with a patient-specific short hollow-stem design appears to be a good alternative to protect healthy joints with high prosthesis survival and low revision rates in the short-term follow-up.

Shannon Information theory has long been a tool of choice to measure empirically how populations of neurons in the brain encode information about cognitive variables. Recently, Partial Information Decomposition (PID) has emerged as principled way to break down this information into components identifying not only the unique information carried by each neuron, but also whether relationships between neurons generate synergistic or redundant information. While it has been long recognized that Shannon information measures on neural activity suffer from a (mostly upward) limited sampling estimation bias, this issue has largely been ignored in the burgeoning field of PID analysis of neural activity. We used simulations to investigate the limited sampling bias of PID computed from discrete probabilities (suited to describe neural spiking activity). We found that PID suffers from a large bias that is uneven across components, with synergy by far the most biased. Using approximate analytical expansions, we found that the bias of synergy increases quadratically with the number of discrete responses of each neuron, whereas the bias of unique and redundant information increase only linearly or sub-linearly. Based on the understanding of the PID bias properties, we developed simple yet effective procedures that correct for the bias effectively, and that improve greatly the PID estimation with respect to current state-of-the-art procedures. We apply these PID bias correction procedures to datasets of 53117 pairs neurons in auditory cortex, posterior parietal cortex and hippocampus of mice performing cognitive tasks, deriving precise estimates and bounds of how synergy and redundancy vary across these brain regions.

Introduction: Megaendoprosthetic reconstruction of bone defects in skeletally immature patients has led to the development of unique complications and secondary deformities not observed in adult patient cohorts. With an increasing number of megaendoprosthetic replacements performed, orthopedic oncologists still gain experience in the incidence and type of secondary deformities caused. In this study, we report the incidence, probable cause and management outcome of two secondary deformities after megaendoprosthetic reconstruction of the proximal femur: hip dysplasia and genu valgum., Materials and Methods: Retrospective analysis of 14 patients who underwent primary and/or repeat reconstruction/surgery with a megaendoprosthetic proximal femur replacement between 2018 and 2022., Results: Mean patient age was 9.1 years (range 4-17 years). Stress shielding was observed in 71.4%. Hip dislocation was the most frequent complication (50%). While four dislocations occurred without an underlying deformity, secondary hip dysplasia was identified in 58.3% (n = 7/12) of intraarticular resections and reconstructions, leading to dislocation in 71.4% (n = 5/7). A genu valgum deformity was observed in 41.6% (n = 5/12). The incidence of secondary hip dysplasia and concomitant genu valgum was 42.9% (n = 3/7). Triple pelvic osteotomy led to rebound hip dysplasia in two cases (patients aged < 10 years), whereas acetabular socket replacement led to stable hip joints over the course of follow-up. Temporary hemiepiphyseodesis was applied to address secondary genu valgum., Conclusions: Patients aged < 10 years were prone to develop secondary hip dysplasia and genu valgum following proximal femur replacement in this study. Management of secondary deformities should depend on remaining skeletal growth. Stress shielding was observed in almost all skeletally immature patients., (© 2024. The Author(s).)

Introduction: Indications for reverse shoulder arthroplasties (rTSA) have increased since their development by Paul Grammont in 1985. Prosthesis design was enhanced over time, but the management of the tendon of the M. subscapularis (SSC-tendon) in primary rTSA is still a controversial subject with regard to perform a refixation or not., Methods: 50 patients were randomized in a refixation group (A) and a non-refixation-group (B) of the SSC-tendon in a double-blinded fashion. SSC-function was assessed at baseline before surgery, such as 3 and 12 months after surgery. Constant-Murley-Shoulder Score (CS), American Shoulder and Elbow Surgeons Score (ASES), strength, range of motion (ROM), and pain on numeric rating scale (NRS) were measured in all examinations. An ultrasound examination of the shoulder was performed for evaluation of subscapularis tendon integrity at 3 and 12 month follow-up visits. Pain was evaluated on NRS via phone 5 days after surgery. Surgery was performed by a single experienced senior surgeon in all patients., Results: Patients with a refixation of the SSC-tendon and primary rTSA had improved internal rotation [40° (20°-60°) vs. 32° (20°-45°); p = 0.03] at 12 months of follow-up. Additionally, the A-group had increased CS [74 (13-90) vs. 69.5 (40-79); p = 0.029] 1 year after surgery. Results were strengthened by subgroup analysis of successful refixation in ultrasound examination vs. no refixation. No differences were seen in ASES and NRS 1 year after rTSA., Conclusion: SSC-tendon repair in rTSA improves CS and internal rotation 12 months after surgery., (© 2021. The Author(s).)